Wednesday, September 28, 2016

Goldenrod Safari

A Goldenrod patch at my home

     This time of year, many people notice how abundant goldenrods are in our open areas. Since this coincides with many people getting hay fever allergies, they wrongfully blame the goldenrods they notice, rather than the ragweed and other real culprits that they don't. Showy flowers such as goldenrods have larger and heavier pollen that is transferred by pollinators such as insects. Wind pollinated plants do not need showy flowers since they need not attract any pollinators, but need to produce an abundance of light weight pollen in the hopes some of it is carried onto another flower. Those plants, especially ragweeds, are what cause the issues this time of year.
     Goldenrods are an important and abundant Fall flower. Many animals depend on them. We have close to 50 species in Virginia alone, so they're adapted to many growing conditions, but most favor open, sunny locations. Due to their adaptability and showiness, many goldenrods are garden staples, both here and in other countries. In some parts of the world however, due to their adaptability, North American goldenrods have the potential to become invasive. They have some allelopathic traits, exuding chemicals that inhibit the growth of certain plants (such as maples) that also help them compete.
     The Genus name "Solidago" translates to "making whole" and points to worldwide use of this plant group for many medical and other uses. In  North America, famed ethnobotanist Daniel Moerman listed too many uses by native peoples to cover here. I will mention just a few for one of the most common species, Solidago canadensis, Canada Goldenrod though: The Iroquois used it for such various things as treating body pains, using the roots as an emetic to induce vomiting, and even to assist in getting better luck, deeming it "gambling medicine" as did the Navajo. The Potawatami used the blossoms for dealing with fevers. The Zunis chewed the flowers when they wanted rid themselves of a sore throat. The Shuswap believed a bath made from goldenrods could assist a mother at childbirth. The Meskwaki believed it could be used as wash for children who did not talk or laugh. The Thompson used it for everything from treating diarrhea, to using it in steam baths for treating paralysis and cripples, to using it to treat cuts and sores on their horses.
     Francis Porcher, a Confederate doctor charged with finding local sources for medicines no longer available during the Civil War, also found uses for it. He wrote that it could be used for cordage, making usable rope. He also said it made for a medicinal tea and a valuable dye.
     In Europe, their species had long been used. According to folklorist Jack Sanders, it was greatly revered. He noted that herbalist Nicholas Culpeper called it a "sovereign wound-herb, inferior to none" and that English herbalist Donald Law deemed it "as much a panacea as any plant could be." More fanciful uses were attributed to it by diviners and witches. 
     Thomas Edison was a big believer in goldenrod use. He experimented and succeeded in making rubber from certain Solidagos. He even bred his own type that grew to twelve feet tall to maximize the rubber compounds. Henry Ford even gave him a Model T with tires made from his goldenrod rubber. 


European Honeybees make great use of goldenrods this time of year, benefiting us with honey.

     Of course, it is wildlife that have the most uses for goldenrods. In addition to feeding on the many insects that use Solidagos (see below), birds such as goldfinches, juncos, pine siskins, trukey, indigo buntings, and various sparrows all feed on the seeds. Despite the chemicals in them that made them such sought after medicinal plants, mammals such as rabbits, voles, mice, beaver, muskrat, groundhogs and deer (although others consider it deer resistant) all make use of it.
     Insects make the most use of them (and feed such things as birds and bats in the process). A study in 1996 found 103 species that fed extensively on Tall Goldenrod (Solidago altissima), while another on Canada Goldenrod (Solidago canadensis) in 1948 collected 241 insects on it over a year. Over 13 species of grasshoppers favor them, as do 16 bug species, 9 aphids, 7 leaf hoppers, and countless beetles (including 15 leaf beetles). Caterpillars numbering 115 different species have been documented feeding on goldenrods (and which then of course become the main prey of birds and bats). Tons of pollinators visit the flowers, including 7 bee species that are oligolectic, requiring that specific pollen in order to be able to reproduce. One species for example, Andrena solidaginis, even has Solidago as part of its name to show how necessary it is for its survival. There are several galls that are particular to goldenrods also. These in turn have certain resident and parasites that will also live in them.


Goldenrod Bunch Galls are caused by a specific gall midge, the Cecidomyd midge Rhopalomya solidagnis. Note that its scientific name contains the genus Solidago, showing how they live no where else.
The Goldenrod Round Gall is caused by the tephritid fly Eurosta solidagnis, in our area usually restricted to either Tall or Canada Goldenrods. One of these has been raided and now has a hole in it, likely helping to feed a chickadee or downy woodpecker over the winter.
Elliptical Goldenrod Galls are formed by 2 kinds of moths. This one is  open and so may have emerged already.


     As you can see, goldenrods are extremely valuable plants and deserve to be included in our gardens and landscapes, not simply because of their beauty and adaptability, but for the wonderful wildlife value they have. There was even a movement to make goldenrod our national flower in the late 1800's. It has had to settle for being the state flower of both Kentucky and Nebraska, and the state wildflower of South Carolina. 
     I thought that to show you just how much wildlife like them, I'd take you on a short "Goldenrod Safari" showing just a small portion of the common things you can find making use of a goldenrod meadow, especially this time of year. So enjoy:


Long-horned Locust Borer beetles, yellowjacket mimics, love goldenrod. They eat the pollen, pollinating it at the same time. They often kill 2 birds with one stone, mating while feeding on the goldenrod.
Daytime flying Ailanthus Webworm Moths are often found nectaring on Goldenrods.  More on them here: http://capitalnaturalist.blogspot.com/2014/09/ailanthus-webworm-moths.html.
Migrating Monarch and Buckeye Butterflies (such as this one) find goldenrod blooms to be life savers on their travels.
Several very similar looking wasp mimic moths are commonly found sipping nectar on goldenrods, such as this Yellow-collared Scape Moth.
Numerous Syrphid or Flower Flies favor goldenrods, most being excellent bee and yellowjacket mimics.
Bees love goldenrods, like this bumblebee and its larger carpenter bee cousin.

     So the next time you pass a Goldenrod patch, do more than smell the flowers (though you can at least do so with out fear of allergies). Stop by and conduct a little safari, trying to see how many different animals are using them. 

Wednesday, September 14, 2016

Bald-faced Hornets



     Bald-faced Hornets (Dolichovespula maculata) have a mostly undeserved reputation for being vicious, pests and safety hazards. They are actually fairly beneficial insects with a role in the environment. Sometimes called White-faced Hornets, Bull Wasps, or Blackjackets, these wasps are actually not true hornets, but large aerial yellowjackets. 
     They mostly go unnoticed and cause no issues until suddenly someone becomes aware of their large paper nests and get scared. Now these insects, which have been living in that same place throughout the earlier part of the spring and summer causing no trouble, are seen as a danger and something to be feared and destroyed.

The typical paper nest we often do not notice until late in the season or when the leaves have fallen from the trees.

     Most of the time, Bald-faced Hornets are actually beneficial. They hunt other insect prey (including some pests) and bring them to feed themselves and their developing young. They predate on quite a few insects, considering that a nest can hold 400-700 workers by the end of the season. Interestingly, one of their favorite food items are their smaller cousins, Yellowjacket wasps. They also serve as minor pollinators (particularly late in the season when they visit more flowers to obtain nectar and hunt less since they have less young to feed). 

A Bald-faced Hornet worker visits a plum flower.

     A typical nest starts when an overwintering queen wakes up in the spring and finds a likely location to start her nest. Though most of the time they choose a location in a tree from 2'-60' high, they sometimes will use the eaves of a building or other structure that might give some cover from the elements. The queen chews some wood fiber, mixes it with saliva, and then shapes it into the first hexagonal paper cells that will house her eggs. Each egg takes about 6 days to produce young. She feeds and cares for these, who then become the first workers and will raise, provide, and protect the young until the end of the season. A new paper nest is quite small and has the opening at the very bottom.

A small paper hornets' nest at the beginning of the spring.

     The queen then has the sole duty of laying eggs for the rest of her life. The workers (all female) hunt for prey, raise the young, build, repair, and protect the nest. They add new layers and hexagonal cells until the nest attains the size of a basketball, though some are up to 2' long. The opening often ends up near the bottom but slightly off to the side. It is at this stage that many people notice and start to be fearful of the nest. Bald-faced Hornets, though not vicious, will certainly defend their nest. They will each sting repeatedly any perceived threat to their young. Unlike other wasps, they are also capable of squirting venom often aimed at the face of an intruder, and which can even temporarily blind. Here's a short video of a nest and its guards:

                              https://www.youtube.com/watch?v=X3HVOckYGsY

     By late summer or early fall, the queen starts laying male (drone ) and future queen eggs. Unfertilized eggs become male. The new queens tend to be larger and are hairless (unlike the female workers who have very short "hair" (setae)). Egg production starts to taper off, and eventually there are no more workers or reproductive eggs laid. The old queen dies (some say that in some cases, the workers kill the no longer useful queen). All but the new queens after mating will eventually die off, usually by the time they get a couple of hard frosts. The old nests are durable, easily visible in the winter when the leaves are not around, but start to rot away, with no workers to repair or lap them dry after storms. Nests (except maybe a very few in the deep South) are not used again.

An overwintering Bald-faced Hornet queen.

     The new queen finds a sheltered location to overwinter, often under bark or logs. She will remain in this state (called diapause by some) until mid spring of the following year when she finds a new nest location and starts the cycle all over again. Here's a short video of one I discovered under a log that was overwintering:

                              https://www.youtube.com/watch?v=3JdiA-Ozddw

     Sometimes nests do become a safety hazard where they might cause issues with people. This is normally when the nest is too close to habitation or where people can bump into them. When this happens, the nests do need to be destroyed, as they cannot be safely moved. This is best done by a professional. If someone does decide to try and eliminate a nest on one's own, please do so with caution and not use such ridiculous tactics as burning them. This should be done at night (when they're all home, sluggish due to lower temperature, and trapped inside) using one of the commercial hornet sprays. A flashlight may help to find the nest initially, but should be placed away from the person spraying or turned off so as to not give the workers a target if they come out in defense. The spray should be aimed directly into the opening, not only to get the pesticide inside and not hit unintended targets, but to also to help prevent them coming out against the stream of the nozzle. 
     Most of the time, these insects should be left alone however. They are beneficial and will leave people alone as long as they don't perceive them as a threat. This year, perhaps because of environmental conditions, we seem to have more nests around than other years. The nests I seem to be finding are much lower down than I typically find also. Old country lore claims that you can foretell the severity of snow by observing how low hornet nests are. The lower the nests are, so it is told, the more snow we will get. There doesn't seem to be any scientific reason that this would work, as the hornets are dead long before the snows arrive and so it doesn't matter where they choose to build, but if this is somehow true, we're in for a really deep snow from what I've noticed this year...

Thursday, September 1, 2016

Walnut Caterpillar

A Walnut Caterpillar. You may be able to notice where it spit up on my hand.

     The Walnut Caterpillar (Datana integerimma) is a neat caterpillar with a mixed reputation. One of 13 species of what are sometimes called the Handmaid Moths, the Genus Datana, they can be difficult to tell apart. They all are very social, at least while young caterpillars, forming large groups. When disturbed they also all have an interesting defensive posture. They all in unison lift both ends of their bodies and arch themselves upwards. They may also regurgitate onto anything that attempts to grab them. Older caterpillars sometimes just let go and fall to the ground.

A Walnut Caterpillar starting to give the typical defensive posture of the Datana moths.

     The Walnut Caterpillar is much easier to tell apart than the others, lacking much of the markings the other members of the family have that make them all look so similar. They do indeed feed on walnuts, hickories, and pecans (some claim they feed on a few other species, but that's debatable). This can lead to their being considered agricultural pests, though that's more of an issue in the South where they can have multiple broods and defoliate production trees. In our area and further North, they only have one brood and so usually are not as much of a problem and the trees recover well. They are also a favorite food of many animals, so their numbers are usually kept in check. 
     These caterpillars have what maybe a unique behavior as well, that even other members of their Genus lack. They all molt, shed their skins each time they grow, in unison. Even caterpillars born at different times and of different sizes, all somehow synchronize it so they all shed their skins at the same time and in the same place. This usually results in a huge pile of caterpillars and then left over skins, in what may resemble a big hair ball, in the crotch of the tree.

The remains of the synchronized molt of the Walnut Caterpillars in a black walnut tree.

     As quickly as they seem to have appeared, they all seem to disappear. The last instar (molt) crawls to the ground and pupates underground, starting the process again the next summer.

Wednesday, August 31, 2016

Handsome Trig - Red-headed Bush Cricket

A male Handsome Trig

     One of the most attractive local crickets we have around is the aptly named Handsome Trig (Phyllopalpus pulchellus). The name "Trig" refers to the family of crickets, Trigonidiinae, or Winged Bush Crickets, with 6 species worldwide, but only one in North America. The "Handsome" part is obvious. The scientific Genus name refers to the over sized, leaf-shaped mouth palps. "Pulchellus" means "pretty" or "beautiful" which is very appropriate indeed. I like this much better than its other common name: Red-headed Bush Cricket.
     Whatever you call it, this small (7-9mm) cricket really stands out. Some think the color combination may be protective in that it may mimic toxic bombardier beetles or perhaps jumping spiders. They feed on vegetation and do tend to stay in bushes. The males, as in most crickets, sing (stridulate) using their wings. The females have an extra middle extension, the ovipositor, used to lay eggs. 

A female Red-headed Bush Cricket.

     This is the time of year to keep an eye out for these handsome red-headed bush crickets. If you're lucky, you'll be rewarded with seeing these neat little songsters before they jump away.


Tuesday, August 30, 2016

Buttonbush

Tiger Swallowtails enjoying Buttonbush blooms.

     My all-time favorite pollinator shrub is Buttonbush (Cephalanthus occidentalis). I've not only seen tons of bees, butterflies, wasps and even hummingbirds nectar on the fragrant white globular flowers, but you'd be amazed at all the pollinators who visit the flower heads at night. I've seen many moths, beetles, and other nocturnal fliers attracted to the white blooms and their perfume. Few people of course are out in wetlands to witness these night time visitors.

A Bumblebee and Tiger Swallowtail share a Honeyball treat.

     This wetland shrub goes by a great variety of common names, most associated with either its habitat or flowers: Honeyballs, Button-willow, Pin-ball, Little Snowball, Pond Dogwood, Crane-willow, Globe-flower, and River-bush to name a few. It's scientific name is derived from the Greek for "head" (Cephalo) and "anthus" (flower). Occidentalis refers to it being from the West. It is in the Coffee Family (Rubiaceae). There are 6 other members of the genus.
     This multi-stemmed shrub can grow to 20' (though 5'-12' is more typical) right in the water, though it can take drier conditions as well. It has whorled or opposite leaves and stems. It is often one of the last native trees to leaf out in the spring. The leaves tend to turn yellowish in the Fall. Where it gets sufficient sun, it can bloom profusely, and often for more than a month at a time. The seed heads are round and to some look like old time buttons, thus its most common name. They can hang for most of the winter on the branches. The seeds float and can also get stuck to birds, both of these being the primary means of seed dispersal. 

The winter seed heads.

     At least 24 different bird species have been recorded eating the nutlets (about 8 of these being waterfowl). Nineteen different caterpillar species have been found to feed on it as well, despite the leaves having the toxic chemical cephalathin. But again, it's the large numbers of pollinators that visit this plant that is what really stands out, whether day or night. Here's a short video to give you an idea of its popularity:

                         https://www.youtube.com/watch?v=byOU5rKbwm0

     According to noted ethnobotanist Daniel Moerman, numerous Native American Indian tribes were recorded making use of this woody plant. The Chickasaw made a poultice from its roots to treat sore eyes. The Choctaw not only used the roots for their eyes, but also chewed the bark for toothaches and made a bark tea for both dysentery and fevers. The Kiowa used a root solution for hemorrhages while the Koasati used buttonbush to treat rheumatism and sore muscles. The Meskwaki used the bark to induce vomiting. The Seminole made the most use of it, using it for headaches, diarrhea, urinary disorders, constipation, menstruation, fevers, stomach aches, and as a laxative. 
     During the Civil War, Confederate doctor Francis Porcher was tasked with coming up with homegrown alternatives to items no longer available due to Union blockades and war shortages. Calling it crane-willow, he recorded that a decoction from the roots could be used for persistent coughs and as an anti-venereal. He claimed it made a pleasant syrup for lung issues: "It is thought by many intelligent persons to be a radical cure for consumption." 
     Some people have discovered that this makes a great garden plant. In addition to its fragrant, pollinator favorite blooms, it can take some difficult growing conditions. Its tolerance for wet feet (it is considered a wetland obligate plant) makes it a good choice for rain gardens and to deal with erosion control. It can also take some severe pruning, having evolved to having beavers chew on it. The seed heads (achenes) give winter interest. Of course, few plants can hold a candle to it for butterfly and pollinator gardens. It is easy to see why I consider it my favorite pollinator shrub.

A Pipevine Swallowtail on Buttonbush.

Wednesday, August 17, 2016

Spined Micrathena - Spiny Orbweaver Spider


     If you've taken a walk in the woods lately, you've likely run into a spider web. Chances are pretty good it was the orb web of the Spined Micrathena (Micrathena gracilis) or Spiny Orbweaver Spider. It is one of the most common woodland spiders, and it commonly builds webs across trails. Why does it always build its web across a trail where something will run into rather than parallel to the trail? Because those same trails used by people and larger animals are also the most likely to be used by the flies and other small insects that make up the vast amount of prey for these bizarre shaped spiders. Though they are a nuisance, they are harmless to people. 


Spiny Orbweavers are spiny and hard indeed.

     Female Spined Micrathena Spiders have 10 spines or points above their bodies and are cone shaped below. They can come in a variety of colors, but often are darker below and lighter colored (often white, yellow, or orange) above. This is a form of counter-shading, helping to camouflage them in the dappled light of the forest. They hang head down in the center of their webs, and from above match the darker forest floor, but from below match the lighter colored sky. They can get to about half an inch long and only the females build webs.


When looking at the bottom portion, the body is cone shaped.

     The males are rarely seen. They only have two spines and are very slender, being only half the size as adults than the females. They often station themselves near a female's web seeking an opportunity to mate with her. They have to be careful or the larger female will eat them. 
     The Genus Micrathena is derived from the Greek adjective for "small" and the Greek goddess Athena, who was the patron of the spinning/weaving arts. There are about 100 different species in this Genus, but only 3 in Eastern North America (with one additional one in the West). Micrathena gracilis, the Spined Micrathena, is the most common and ranges all the way to Costa Rica. Its specific name means "slender, slight, or graceful." A neat little name for these web builders. 
     The hard spiny body of the Spiny Orbweaver is likely a protection against predators such as birds and lizards. Since the spiders rarely if ever bite, this is important. They will often try to scurry away to a corner of their web if disturbed. They will also sometimes play dead, lying there immobile with their legs tight against their armored bodies. But their most interesting defense is the low pitched buzz (stridulation) they emit when scared. Next time you approach a web, blow on it and see if you can hear it.


When frightened, Spined Micrathena Spiders may pull their legs tight and rely on their armor for protection.

     Micrathena Spiders are in the family Araneidae, the Orbweavers. Their spiral webs are usually less than a foot across, but are placed 3-7 feet up high, perfect height for someone to walk into. When sunlight hits them, they can be really showy, giving them another common name: CD Spiders, since it might appear as though someone had strung one up across the trail.
     Unlike many other orb building spiders, Spined Micrathenas are diurnal, active during the day. They actually eat their webs (all but the supporting frame threads) every night. It takes them about an hour to build their webs again the next morning. About two thirds of their prey are Diptera, or flies. Spiny Orbweavers are a bit slow and clumsy, so their prey gets away a lot. They also differ from many other spiders in that they bite their prey first before wrapping them up, just the opposite of what most other orb web spiders do. 
     These small and common orb web spiders only live about a year (the males not even that long). By late summer and early Fall, the females will lay their eggs in a fuzzy egg sac hidden off to the sides of their webs. The adults all soon die, but the eggs will overwinter and young spiderlings will hatch out to spread through the forest the next spring. 
     So the next time you run into a web in the woods, it may be that you just destroyed the handiwork work of these little spiders. Before you curse them too badly, remember that they're harmless and doing you a favor by catching flies and other small flying insects. If you see one of their webs across your path, enjoy the craftsmanship along with the unusual color and shape of their maker. 



Monday, July 18, 2016

Cicada Killers or Cicada Hawks

A female Cicada Killer attempts to carry off her prey.

     Eastern Cicada Killers (Sphecius speciosus) are large, solitary wasps that go by several other common names: Cicada Hawks, Sand Hornets, and Giant Digger Wasps for example. They are in the family Crabronidae, which has 4 species in North America and 22 world wide, all specializing in preying on cicadas. Their scientific name translates to "Wasp" and "showy" respectively.
     They certainly do stand out. They're big, up to 2 inches for females around here. Though solitary, males will form territories around good nesting habitat, guarding what are called leks, or breeding grounds. Since they buzz loudly and fly up to investigate anything flying through their territories, they can be quite intimidating. They grapple mid air, sometimes crashing to the ground while engaged with one another, scaring people in the vicinity in the process. Here's a short video of a male guarding a hole, waiting for an available female to stop by:

                    https://www.youtube.com/watch?v=G8BAQnAKyfI

     Recall however that stingers on bees, ants, and wasps are modified ovipositors, used for egg laying. Since males do not lay eggs, they cannot sting. They do have what amounts to hard tip on the end of their bodies though, a pseudo stinger that can poke, but again, this is all bluff.
     Here's a look at some cicada killers mating: 


     Females Cicada Killers can sting, but almost never do. Researchers have had to hold them in place to illicit stings, and supposedly the stings are no worse than a pin prick. They would only sting if caught by hand, stepped on barefoot, or got trapped in clothing. Walking or mowing over them will not aggravate them into stinging.
     Many people confuse Cicada Killers with the large, introduced European Hornet. These large yellowjacket-like wasps are capable of nasty stings. Since they also hunt large insects, seeming to like to eat cicadas as well, they are often called cicada killers when indeed they're not.


A European (German) Hornet attacks a Cicada. They're often confused with Cicada Killers. A smaller Yellowjacket hovers overhead.

     Female Cicada Killers require a cicada for their young to develop. They hunt for them, stinging them until they're paralyzed. Although you'd think they catch more male cicadas who are singing and advertising their presence than females, they seem to get an equal number of each. They go after the various species of "annual cicadas" (those that come out every year, but whose individuals may spend several years feeding underground). The Periodical 13 and 17 year cicadas have evolved to emerge earlier and are done breeding by the time Cicada Killers usually emerge. After stinging a cicada, they carry their prey back to their burrows. Since the weight of a cicada, especially the larger females, is 2-3 times the weight of a female Cicada Killer, that is no easy task. Here's a short video from the Capital Naturalist YouTube Channel showing one attempting to do so:


                       https://www.youtube.com/watch?v=5sdzhAuvBtU

     Cicada Killer burrows average about 6 inches deep, but can go deeper than 2 feet. The females excavate them using their jaws to loosen the soil and then pushing the dirt back out the holes using modified spines on their legs. This means that they are very picky about where they build their nests. They like to choose bare, loose, well drained (often sandy) soil, sunny if possible. Sometimes 2-3 females will share an entrance, but each then digs burrows away from the main tunnel to use as their own chambers.

     Each female has a cell she provisions with the paralyzed cicadas. She leaves one cicada if she decides to lay an unfertilized egg which results in a smaller male Cicada Killer. She will leave 2-3 cicadas if she decides to leave a fertilized egg, resulting in a larger female wasp. Thus the males are smaller, much smaller if they were provisioned with a small male cicada. Eggs are placed under the second pair of legs of the paralyzed cicada. Females sleep in the burrows at night.


A lek, or breeding area, full of Cicada Killer burrows.

     After a couple of days, the eggs hatch. The larvae feed for about 2 weeks, feeding on the cicada, leaving its vital organs for last so it can stay fresh longer. The young pupate and overwinter in a cocoon, emerging in late June or July of the following year.  All adults die after breeding, none making it past the Fall. Adults nectar at flowers and feed on sap flows, being very minor pollinators.

     Though these huge wasps, among the largest in North America, can be intimidating, they are harmless to people. It is unfortunate that they sometimes choose our lawns, garden beds, window boxes, and playing fields to sometimes build their burrows, but these are beneficial insects. They can be discouraged by mulching or heavily planting the areas they favor, but should just be left alone otherwise.